Longitudinal muscles are composed of unstriped fibres.Muscle layer is composed of an outer thinner longitudinal and inner thicker circular fibres.It is derived from the visceral peritoneum and is composed of flat squamous epithelial cells, called as mesothelium. Serosa forms outer covering of duodenum.Section shows serosa, muscle layer, sub-mucosa, muscularis mucosa and mucosa. HIstologically duodenum resembles with ileum but its mucosa is peculiar.Identification: Since the section has thin epidermis and thick dermis and above features, hence it is V.S. When the cells of stratum corneum die, they are shed off and this is called as moulting.
#Frog ovary parts skin
Skin is an organ consisting of an ectodermal epithelium, the epidermis, and its supporting mesodermal connective tissue, the dermis. It is protective, water observant, respiratory, mucous secreting, sensory, excretory and swimming. Special features: Skin of frog performs various functions. Connective tissue consists of horizontal connective tissue and vertical connective tissue.Just beneath the stratum compactum is lymph layer and then body musculature.A cellular layer separates stratum spongiosum and stratum compactum.Dermis also contains few vertical fibers, blood vessels nerves and lymph space. Inner layer is made up of compact zigzag parallel fibres and hence called as stratum compactum. It contains mucous glands, poison glands and chromatophores. Outer layer is made up of areolar spongy connective tissue and hence called as stratum spongiosum. It is distinctly differentiated into two layers. Dermis constitutes major part of the skin and is largely made up of connective tissues.Beneath the epidermis is thin basement membrane and then dermis.Multilayered epidermis is differentiated into two layers : (a) outermost layer is stratum corneum and (b) inner layer called as stratum germinativum or stratum malpighi consisting of single layered closely placed nuclei. Epidermis is thin and made up of startified squamous epithelium.Vertical section passing through the skin reveals two layers, outer epidermis and inner dermis, distinctly seen under high magnification.Identification : Since the section has thick musculature and mucosal folds and above features, hence it is T.S. The secretion of the gastric glands is under neurohormonal control. Pepsin breaks peptide bonds and converts proteins into derived proteins i.e., peptones and proteoses. Special features (functions) : As soon as food reaches into the stomach, its muscular walls masticate the food its gastric glands secrete digestive enzymes which hydrolyse the food. Mucosa contains, oxyntic cells (HCL secreting), zymogen cells (pepsin secreting) and mucous cells (mucus secreting). Mucosa consists of endodermal columnar epithelial cells, and connective tissue. Mucosa is the innermost layer thrown into folds.Muscularis mucosa is a thin layer consisting of longitudinal and circular layers.It serves to bind loosely muscularis mucosa with the muscular coat.
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